The Facebook 5 update applies to Facebook’s iPhone and iPad apps. On its blog, Facebook said the app has been rewritten so it’ll not only open faster, but news feeds and notifications will load right away. When scrolling within the app, Facebook says friends’ updates will “appear faster than ever” and there will be banners letting you know when new stories are added.

That rewriting of the code means moving away from an emphasis on HTML5 for the iOS app, which Facebook has been relying on in order to address the needs of thousands of different devices that access Facebook. AllThingsD has the details on why Facebook chose to deliver a native iOS app with this update instead:

While the current Facebook app is predominantly HTML5-based, [Facebook iOS mobile project manager Mick] Johnson and his team gutted it and rebuilt it using the Objective-C programming language, which essentially makes better use of the iPhone hardware and focuses on the advantages of using a native application, rather than render Facebook items in the app using Web data.

This doesn’t mean that Facebook is abandoning HTML5, Johnson says. “The mobile web is still very important to us, as are all of our interfaces,” he said. Problem is, HTML5 is a technology that, while promising in the long run, isn’t able to deliver the type of speed and performance we expect right now. It’s a long bet, and something that Facebook aims to continue developing.

This is one of those updates that should have been done a long time ago. Facebook is the most-downloaded free app in Apple’s mobile app store, yet the reviews are scathing — and have been for a long time. Why is Facebook getting its act together on iOS just now? It probably has something to do with Apple integrating Facebook into iOS 6, set to be released in a month or so.

Facebook didn’t leave out its Android users: updates for both iOS and Android are waiting in their respective app stores now.